Physical cryptographic attacks exploit implementation-specific characteristics of a computing device to provide additional information that may be used to assist in obtaining the secret parameters used by the computing device in cryptographic operations.
Generally, physical cryptographic attacks may be categorized into three broad categories: invasive attacks, semi-invasive attacks and non-invasive attacks. Invasive attacks, such as de-packaging the computing device to allow for direct probing of device operations, may be resisted by constructing tamper-resistant hardware with sensors to detect the invasive attack. Semi-invasive attacks, such as using laser or ionized beams to induce faults in the device operations, may be resisted by including fault propagation in the circuits of the device to amplify the induced fault or by including consistency checking of results to detect and correct the induced faults. Non-invasive attacks typically use externally available physical measurements of the computing device while performing cryptographic operations to provide additional information that may be used to break an otherwise secure cryptographic operation.
Non-invasive attacks that are passive, ie pure measurement without interfering with device operations, are commonly known as “side-channel” attacks and pose particular challenges to computing device security. Side-channel attacks exploit the physical implementation of a cryptographic operation on a computing device, without taking any direct action on the operations of the computing device.
It would be advantageous to provide for a hardware countermeasure that improves the resistance of a computing device to cryptographic attack.
Similar reference numerals may have been used in different figures to denote similar components.